SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e26bb2296e4a7d67f865e247db3a65ce9b2d6fef23f931acff128ab668529fc0' 
  AND token = '/andOITUaFjVYSY+ZGriWJzXQusRKni4PkAL0wCdkFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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