SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6b7a77c3fa6466c32409be6724d2b619e232582ca0efd3fef5fa899b4188c49' 
  AND token = 'STSVxjJgH7rTGXqPP2GmZTgYT2Hv7m3/Pzio8kCSkwQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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