SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d37fac323d0fd961ce2afc78485d908f6fcc9d03c45f17d55422ca5b67be742' 
  AND token = 'idesrUS8cN1ztzNh2q1S6SDMVmjhSJdhBHl7c9niGPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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