SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98d4d1e3128e1e7585728a28b19f0ed239d472716838a1ed870bf57c88b0d8c0' 
  AND token = 'v0O3aTFPTuBxKLFQZkHpAZE8b8nyOJ3yIao8E1h9evs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}