SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9dd277641d9c9e6ba32b6400bad9415ab623b1de7fb2c43c934e4fde88dcc30' 
  AND token = 'GS3aLmpVr+CEdPsH8SXQK5xnvpkZSXY2/pzOojMphbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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