SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fee098d2b304ace8a6d6972957cc22b658f2e5a654c7f4d335cd55497e2d3f1c' 
  AND token = 'gC4QUEfwo7JLN2YtekTl2GjPF8tV3LRxy/DcADqQKKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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