SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c79680cdf78b9565bab246003c82d76d0105410204130e65319778856a6de74' 
  AND token = 'MBqN/Hv7TdSzCYGGkbTy8ZsfQArqSVEYsThzDY37LsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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