SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fe7c06dd42ae136b9ddda29be9c853f3323c59644d3ff9beefd49b2be1ede08' 
  AND token = 'P4ycdVRUIWvo0SheQsdG+QB6WBdZpQDtMaDzTFXhIDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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