SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f7c3e35e0b375b535a688c886c8ac3faf875d89f8aac363fa10c407cfd94393' 
  AND token = 'JDIVZPo3MPxE09TKBdNvbtq9dpxDPZdDYkdYsDQy1Nc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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