SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac7fefb5747191a5bd5aa9c2fafc81f14bf72f1bd364b683b4ae2279640d6bc6' 
  AND token = 'pmhObidZmllWjRNmrQuiTV9Eq+JR19dBTBVdAzsBOZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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