SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0050051d8d6bc92c326bb39ad247fe924dea08314eb9269ce1e94cbff46101e1' 
  AND token = 'JcxwkDJL6AbYpDG2uMxEMDTcZLvzSqZ2B4ujxnvZUaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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