SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b25af816b857343afb00d96bd218f1e314cee34cb073d1bb8784f52eda68bb3e' 
  AND token = '7sczc8PSKRD9E0RPCxf/mcegNqPKoV+d57aCrHJd0Ic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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