SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '916df513f08777d07732c31eb2faa051abe36d1a5309dc0091b556f1e678e6b6' 
  AND token = 'XEJIC+rXSEqe9OoqBKfGXUEtl6oacEGcrklPhgBdIws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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