SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a745552f8450972aeb8d3ff141d0d7177d1e77c3a5a2e3162a6a1c41091c32f2' 
  AND token = 'QHLuBnB5zFndIraw9NwQ13A0ejkUgB+YARFk5ar4C10=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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