SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c13008b104f05cc183debe0ff5150416ca92f8ff67494afd3cb246364f588172' 
  AND token = 'kO8GHWzNIoPZ7FJC57+Oj+WHNmG2142H5ql7o56wTBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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