SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df5edc1382064e7d0e852e1a0de1685f0a64fd113cf6e3b1c082dcbafd524b5c' 
  AND token = 'Da6th/UUg2TGcEqX/M8drooyyczXfrHiLacZpKXpAdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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