SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3b60d6e89c97c76854a5a1648c9b25afeed4f3634eb5db7b5c2382253712900' 
  AND token = 'tmT3yXbJ+DKadItJRim0QAU8WZ+ozXsBHoBmVESMGu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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