SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03d3fbc2554cc81b31977ec8582ee7cd26bd0cc90a5e97f1047ee851dd69fd43' 
  AND token = 'wN9DUjQJQSRSHyJ5xKj5Hyb+JD/fk5UrH0nIVsUAOtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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