SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c68cb20d567294524f4d5b6f7763e318bf814af7896ddb2a2652e1a1c95b7edd' 
  AND token = '/w6iKC+FI/5VpuKOU0PflW3qfOmCZG+e3e9A9F8og7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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