SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '881f362308af37e195d7cc7cad6984b846dc420f90101fa0228bda763f1eb3ed' 
  AND token = 'O8GAqwwYCmNykACnyr3URwyCWFBA86wyj5A3tOl4Ay0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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