SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9748f5fa4e7c6c5be289e17c39217aff96424bc04dac500100a28d85531d4f3' 
  AND token = 'frqnAWwaEfZLO21dGvX/3a9QGU8DutmgmzOC8HsjtCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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