SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85d3016ba94d23329d49933dbdf4766ec25352fd55c2b9f1674e576a98b1f538' 
  AND token = 'mB76rOOZnZv/siilxaFhq2QGby0UxkmfX+LGlhbMV0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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