SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3267ed58379bd1ba8f6897117aae63b176c064535e9a4df6a1d82b95774d577a' 
  AND token = 'uvFTCj1l69uf3JbRZpEYTS8phIBHwukteqfg+gGBX1o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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