SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0a43a61fb37e4e8c609054918d5b5ca5a376b70d1189151b353c9c8abc4c126' 
  AND token = 'QLIj4OUKF3z9V0myn3vS0+f+8X/XoeZgctF7PqpMBl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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