SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5b0d62b2ea3202b778d795e82cdecd08149d753802e7f9e70bb45188d1cd63b' 
  AND token = 'UStSlF7UuC6oXdnjjgsth0HUrVjPI43cu71aNnkf6EI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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