SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f53967419b15e2e26e20e20a55588e017f527a986a391ad24228bdfab2aa1739' 
  AND token = 'LHLy9f1y+K3SoQy4hWrACB2m2XIJAlS7rvb5b0z65Po=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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