SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f854d883c786d30dff114e2aa7e571d763cbb7985914e342c2fcd0cafcba4573' 
  AND token = 'iiJmxzsOTys/fKQU54U/ERDdeSmq4XdNRLT/DahFHuc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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