SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3d696db8b9f2dca0ad94a8965fd877e1db897f4a21c23adbda82c7d8b61cff4' 
  AND token = 'z86b10MifsroXToX5oh8hOTIZlJ7TvjmxSBo5HBXp8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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