SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6e01b61d2448ecc18c0cc578d02b9a778b242a833d4f52eef305a5b2197c51a2' 
  AND token = 'P/ViGF6wYLCvc4QBcllREm7clAmhTm3psPnMOcloako=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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