SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '921edea35241433b520e54b24d94d3f19ea759bbeea135a752657dd01065bb42' 
  AND token = 'EXdRE0kYbyu/PprrkagffNV4dN13HSvzhO3nS66mTGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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