SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a3616188e55c0fd8a8a7353c3b1d6cab9cf8e358c7b6a244cbf1b6ad88e9aff' 
  AND token = 'kMUrt1zbCLXOe1FOem7hryKuxMIP38L0b1WioonF+Fo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}