SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5cf9b61e185d71aee385e0cdfb88d76d620e2b6d4ac046427ec7db05bb4f47d' 
  AND token = 'REeVAqahCCEyZ/ywFvimMgXcTbLVa/K2QGkV1/bMmko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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