SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '424df3714d10050692ea551cad706f884d16f630ee7e426a1f6591ae0f1821eb' 
  AND token = 'oObv32XsEy3KS1crWv9AWJCXKop/P8y1U3eLfnsIDJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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