SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82340d550ee109bb268029bcac72692af7728c5cd300fcdf8d3a784060fe7ad6' 
  AND token = 'YRQbyvcHrveqg0PLE/PlEM2hktHMzLVxDAoBYZ7yy68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}