SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26dcaa8225437dce5fdff3aecdd4fc258eae8f8b4be6c48248e7c31c43bc0334' 
  AND token = 'pkz+FBUpJElBSzPuHdBQfa2Y6OttyvMUI9eNwgSPca4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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