SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfb8bc6a93d08a4888e67c337d8c1cf20529177eecef913aca7cbdacb5467987' 
  AND token = 'jROVSjhp+mOJFNDUzjUpyTLWU3eUT/yjlOQZgYBQYWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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