SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd10fba059b08b84debd61cb103fe730de27c52de84021627afdb8702d19da1d6' 
  AND token = 'lfSPz3ipD8hHMb1CNeYfZBlcjRitctW9ZRGcDgR+kjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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