SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78e74e61362e5bfb92d4795ddc6a8b7b2f37838cf7d41847591bab3b3ec1e44e' 
  AND token = 'j4iBiYNZ8krl8L6/mP42Go+I9MVZm9Yy3lY1G9zwqIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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