SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a81d936b2d850b95dbccc4b6e3bbe3df282406d918a03fd3d47f5874dd70461' 
  AND token = 'egjXOn2b+eWtPgYiLVq+nwUOmhTyA1uIvnA0ufXEnMI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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