SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c6992710fe2b5f38feb7fc09d6da60ecb0e6e5add445002fa358326bc9403c6' 
  AND token = 'xFnbi5QdXnLGWvUIJH+SGzrvqR8c318dhhoxPikNqoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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