SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7615a2dc2681bf31c680e076e711450dc67abb0713ac50efaadb22c6f1e27a0f' 
  AND token = 'uMJO+dn3pUJJz6dSsnJEZ889ZLlBIzLdgu07nCiau/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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