SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbb302edfd59666adeb20c8a8040212ec64e10841dd05228d336dc6132f98784' 
  AND token = 'i5MbuJubFYI5dKveMAI1RABGCbjfVkurRAMWHIPxD4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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