SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '953f3753b79806f7cb55d3553fb245245a70016249b2f18e6a71b0e17a9f5e58' 
  AND token = 'VRbw2Qa0DXfxpetTS+AgqGrqRjKbQO0VgcYCZ3/qDpQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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