SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c52b965eb7385b22307b8bdb58f180920e45c407e8332f46281dfb3798679aa0' 
  AND token = 'KiPXMKY8K5FTVW1//x5Bnp+n4/yphPrpVTBc+qc4JSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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