SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a0197bce92e86d515b6fd4a23c3289a70ffba9985c7ca15ab50fd76841495f5' 
  AND token = 'mEkh1onAgo8q9G2/jeuKjyMC3Fm+4Fuvt9eZTtRARgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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