SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a64311216f0e4bc39f2035e9d6e3cd76ea309933eca98a8c39773b526a48b8a' 
  AND token = 'sXTbtFoMuFyHodZ1QUJmMdrVxCenWPZBGqcd21Sq28g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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