SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2077b6d0c7a0253f22795a8893ae210e93dacdc977faa5377e82a8d59b704ed' 
  AND token = 'A1exAeUKivP05K/zjqXfHV5CHDDO23x4aywCDWBMayk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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