SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cecbf2b9c74ef963f6051d65c48e410c4bafcfbebf8b431d30b6cf29638c1a16' 
  AND token = '0is5+NLHW3C3yq9tckrP/wzcmPhvIj63mqeu7Ok79Ww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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