SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb2cb15471440354fb808c6a45f115fdfeabe63f315ea38eae6682521359a266' 
  AND token = 'eL4oz+jXqk++x1wolnEZ1WVijVUuBmuwo/KpG6t/nRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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