SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '83a6c6b7a1a22f44cc9504d94fc25afadd0cd0912752ecb57794d92c2652a6ff' 
  AND token = 'xEsRkvIKiCfjHbAAxPnXMpnap1+uRFxoNXxrFkAvZdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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