SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4c6d49db7daba66e30e72e3df683cb5564d7ed401dd64412665d57bf999c7b9' 
  AND token = 'rCO6vpShvNwbnPc+MyXNryIuy5FOxSIUf8y3nFX5WRg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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