SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3e2373d88c8b25062c07640075e9d1cab0f17eacdcb48610184b9a6ee4e143c' 
  AND token = 'tLkR6WFbU2bpp0DDxvqkIIftVvtIy59bIFRm0cIQiro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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