SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7eabbcfb77c463e140284d2a841363bc86cd287dc27a73e3b937ee3dca0610d9' 
  AND token = 'HObyjtE5ElxDi7rGgtIvNQfs90ToaMXdX+798xsNmlc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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