SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db6551deeb31729588ef4001d66233a68cf4f12e4f215af8c6eb659b1a7a714a' 
  AND token = 'lPZRFVYlhuLHEuhW7D557h/l/ERZi49WHkaSDGOvfjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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