SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48df00fb75d36607acb57e1c2e9000ade5d24486216ab734e498480f8d9f0513' 
  AND token = 'lEYtQMKZScODBmVgSmhWdskgqZycGfyljmOcrevqHew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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