SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b584dfa1cddf8bcf79cf48fe805204c6a704489bdbad80de0478dbc4fbe4af8d' 
  AND token = '8GsZHHVktMx1pWFql/hljaXvcD5x0ozlkd0Ed23TqRI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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