SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40b1bfca9b43ee91a2c398162a3c125084d4e5072ba5233a791ac4ad21f431be' 
  AND token = 'YoR0Vi103OgIsv+JO3jTRdxVTLAYW6Nd+sS77CN2Jec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}