SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e19085aabf95d032dabc232bf835800e824d56feb8c6394596e12baf37701b03' 
  AND token = 'VLJYMtL5uc4bTAcTeNRcU/0FPVzajO+FGOM8m/9BsbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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