SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2616638880252316185c0dcab75f4c672c00cc701082a78fc79c8ac0d3344f3c' 
  AND token = 'cOMWfKBVtvuA6LumEMC6KyCPlDa8lvb/EjXH8HKCWE4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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