SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c941eef44dd351638cbd1bc449013d347803ab1d617c475e30def3fe311ffb3' 
  AND token = 'J4WgwuOwwbtw/bYWTM+KI0Q/fOPGlqfW84P1O/JEZBo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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