SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5e1c1d813475f2f3b02dc3b37eb831d1aa694a041b19a95ab3a658ea89d4cea' 
  AND token = 'd12BvYzV6tG4cjzPCxQKzgxKXyxAFwWTCuwZQXPyxgc=' 
  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"
    }
  }
}