SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c6c22d81d8f7b1e1e1d35ce00a41235ab8a1db7377daeb8aa37e49b2670941f6' 
  AND token = 'VXGSZdhgSu5ffZqDTGzW40Ed+m533c0TaqXORFXYJRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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