SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0840e3b4e7d5b27f510557eafd4e7b3459dded2726b512f38e9b2fcc911e4e5b' 
  AND token = 'nS20TV06yPvmDDxI1Z/cDgjtK4fdc6fSt9swJsjMQgo=' 
  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"
    }
  }
}