SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba4460c2e71f85d1495547de667174a50bb127989468cacc7beaf130d1078a6b' 
  AND token = 'fc6IkKzSUfsDc4O1dgbQjsKiZIqhO+gQLYrhvjVsWco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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