SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59763220cb8ea57d4342f1b174d5b19ec47ff2eeb89047be551693ea8b6f7bca' 
  AND token = '+VSMKR6HBlhN3vgKPjT2Z5Cm8fzlNg13r9lt4vsDbIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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