SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '784184a09870d204c8b4d113082841d267bc6580d9ba97e9090836495e3ec3d9' 
  AND token = 'sjcFL1/VRdTCHLySok1wWlrVMopS0wFiGhceQ9I8qU0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}