SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf7475e0d360cb858907aa1fffab381893f1c0233f1eb152b12ed9543b89d99e' 
  AND token = 'nHPpkWCDgfW/kUOPJDBqqfDwtu/biGqRFAHCysseX0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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