SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b3e55929c5d66ca81e283cfc62de0a979d9b201d22f29347a386d1b54930bd1' 
  AND token = 'bFGRYGrq9WNOK5Jpg0pmRpH295bGgSuNaZAqgZreq+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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