SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46112b13116476a531614b2043fc18286a7330ab3d5762927b6182302344bf0a' 
  AND token = 'JDVgp7tVeSYPJXXzdphS7IRzR6c9YIDHGtwTJTQJnSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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