SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '078163cf940c79a2368a10b55dfaaeb061f26ea0b299d2871173a1ca52326c24' 
  AND token = 'wS2UqVN7n+aKLE0DVvkkcswMAvy2fbiGnfgmwFehji4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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