SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d52c8ef8c0d1c654e679eb28cfd3a77622fd861f083008877490af2ae5db891' 
  AND token = 'y7FbCYSKwcmh9QQ6S8920A3eIwgtLiF5RtJ6F6ygVNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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