SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c60f4566e78f1aecda3846ab9ccaeab75534627698a5ce05bfeb051d027b68ed' 
  AND token = '/Tn6GgL0VC0olrKc35vPgmdmoEtgdgRBwM0XebXHHws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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