SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30ccc4b8d4cb6abb95cdf5f214b1563eba3e60f58c22117c14063da15715d818' 
  AND token = '+wbwGtBhN1wmZ358+NfSwtwhBR6TP2sFE5uhzqobdH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}