SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d3e25a07e758836c65340855a53ea9997f3cd9d68d1f5e34136a9823521554b' 
  AND token = 'Kl5EBCC2Ta057qroAKwgR2+72NlqHxKmzoMrfsPLhww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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