SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f91b8af3b7898c71d27416f73964e19e80d78043a43fbc76e8c133ea640488fc' 
  AND token = 'gPBY+3d3VJ1YCW6/bi/CdAMlihjwoZPQrodiGAqLZiQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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